Brush for motors and generators



2&9 '1936, A. F. LUNQQUHST BRUSH FOR MOTORS AND GENERTORS Filed Oct. 25, 1934 Patented Jan. 28, 1936 UNITED STATES PATEsiT FFICE BRUSH FOR MOTORS AND GENERATORS Application October 23, 1934, Serial No. 749,587

8 Claims.

The principal objects of this invention are to provide a motor for operating an eraser or other implement and a casing therefor, so designed that the casing can be held in the hand and can be manipulated with extreme convenience for the purpose intended; to provide a brush for a motor or generatsr which will be capable of longer life than has been the case heretofore, which will be free from sticking, chattering and squealing, and which has a more uniform contact pressure; to provide a construction in which the use oi a brush material favorable to a longer commutatcr life can be used, and to provide a construction which will lend itself to a rapid and efficient production and assembly.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in which Fig. i is a side view of a motor casing constructed in accordance with this invention;

Fig. 2 is a sectional view thereof on the line 2-2 of Fig. l;

Fig. 3 is a view of the commutator for the motor or generator showing the brushes in position thereon after having been used for a period of time;

Fig. ll is a perspective view of the support for the brush;

Fig. 5 is a perspective View of the brush by itself;

Fig. 6 is a perspective View of the spring for rotating the brush;

Fig. 'l is a perspective view of the retainer for the brush, and

Fig. 8 is a diametrical sectional View of these parts assembled.

This invention is capable of general use but is particularly adapted for a small motor for operating an eraser or other small implement where high speed and considerable sparking make frequent brush renewals necessary. It is particularly adapted for small motors because a larger amount of brush material can be located in a small space.

Referring to the drawing, the motor B is shown as located in a casing 'I of an elongated ovoid shape so as to be suitable to hold in the hand and manipulate it thereby. This casing is of insulating material, preferably made in two parts. It has a starting button 8 placed conveniently on top where it can be operated by the foreiinger and suitably connected with the motor. The shaft 9 of the motor projects downwardly from the casing at right angles to the arm of the operator. The usual commutator I0 is shown and brushes II. Each brush consists of a circular or disc-shaped body of carbonaceous or other brush material and it is mounted to turn on a stud I2 which is provided with a collar I3 and 5 with an integral head I4. The end of the stud is provided with two transverse slots i6.

The brush ii in its original form is circular and of such width as is desired for application to the commutator. It is provided with a periol0 ration I'I in which the collar I3 is located and with a circular enlarged recess i8 for a spring. It is also provided with a radial slot it.

Located in the recess I 8 in the brush is a spring 2I coiled several times into a spiral. One end 20 'l5 of this spring is bent into a diametrical position for being received in the slot I6. The other end 23 is also radial for being received in the slot I9.

The spring is applied to the brush with the portion 23 in the slot IQ and wound up sufficiently 20 tight so that it will have the power to rotate the brush through a complete revolution. It is placed in the recess i8. Then the end 2U is placed in lthe slot I6. After this a retainer 25 is applied to the side of the brush over the spring to hold it in. 25 'I'he retainer is forced over the head I4 which yields and springs back to hold it.

In the operation of the device, a tension of course is on the brush to swing it around in the direction oi the arrow in Fig. 3. The edge of the brush is placed into contact with the commutator and as it wears, the wear will be taken up by the rotation of the brush by the action of the spring. Moving from the initial position, after some wear, the brush will take up the position shown in Fig. 3 and the spring continues to rotate it gradually as fast at it is worn out. It Will be seen that, on account of the several convolutions of the spring, the brush is capable of being rotated practically through a complete revolution and its surface worn down to a smaller diameter by action on the commutator. This device therefore has the great advantage over those brushes, which are pushed radially toward the commutator by a spring, in that a Very large amount of material is available to be used and worn away without occupying as much of the space as the radial brushes would have to have available if the same amount of carbon were to be worn away without changing brushes.

On the small motors on which these brushes are particularly adapted to be placed, an ordinary brush will wear away in about sixty hours of use, whereas this brush will last for a satisfactory length of time- The design is such that the ordinary circumstances and the sparking is ma,-V

terially reduced.

This brush is shown as applied to a small motor 6 having a commutator lil, as stated. 'Ihis motor is mounted in the casing 'i which-is fedvby wires 30. This casing is intended to be held inthe hand and it is of an elongated shape so that itl can be held in the hand, as in-dicatedin Fig. l. When in this position the push button B'for starting the motor is in a convenient position to-,per-` mit the index finger of the right hand, which holds the casing, to operate the button;

The motorv is mounted on an axis, which may be used in vertical or inclined position, and provided with a shaft 9 which extends down through an opening in the bottom of the casing and is provided with a chuck 32 holding a too1as an eraser 3l. While this motor and casing are designed particularly for operating an eraser, it is capable of use for operating any 'smalland rapidly rotating tool, such as a tool for polishing nails,

dental burr, oir any other tool which isdesigned to be moved over a surface for the purpose of performing its function. This casing is a very convenient shape and the relative location ofthe shaft S and the button 8 makes it particularly useful for such operations.

Having thus described my inventionv andi the advantages thereof, I do not wish to vbe limited to the details herein disclosed, otherwise thanY as set forth in the claims, but what I claim is:

l. As an article of manufacture, a brush for use in connection with a commutator comprising a disc of carbonaceous material, in combination with means by which', after being set in' position, the brush will be capable of rotating througha substantially complete circle before it isusedvup and means inside the disc for rotating the disc through substantially a complete circle.

2. As an article of manufacture, a brush for use in connection with a commutator comprising circular disc of carbonaceous material mounted to turn on its center, and a concentric co-iled spring connected with the disc` for turning it through a'substantially complete revolution.

3. The combinati-on with a commutator anda brush therefor, of a xed stud on which the brush is centrally and rotatably mounted, and means connecting the stud with the brush for rotating the brush through a substantially complete revolution automatically as it is worn away.

4. 'I'he combination with a commutator, of a circular brush, a xed stud on which the brush is mounted to rotate, said brush having a recess therein, and a spring located in said recess and Wound up on the stud, one end of the spring engaging the brush and the other end the stud, whereby, as the surface of the brush is worn away, the spring will keep the brush in contact with the commutator and gradually turn it around on its axis.

5.y The combination with a commutator and a circular brush therefor, of a fixed stud on which the brush is mounted to freely rotate, the stud having a diametrical slot at the end, the brush beingprovided with a radial slot at its edge, the brush having a recess therein and a spring having one end secured in the sl-ot in the stud and L wound on the stud in a spiral form and having its other radial end engaging the brush so that the spring will be free to rotate the brush on the stud.A

6. In a commutator, the combination of a stationary stud having a collar thereon and a head separated from the collar, of a disc having an opening at one side in which said collar ts and which centers it von the stud, the disc also having a recess, and a coiled spring in the recess, the spring having ends held by the disc and stud respectively, whereby the winding up of the spring will leave the spring under compression and cause the spring to rotate the disc.

'7. The combination with a commutator, and a n brush engaging it, of a fixed headed stud slit deeply, and longitudinally, the stud passing through the brush, and a retaining collar for holding the brush, having an opening through which the head of the stud can be forced, whereby the head will hold said collar in place.

8. In a commutator, the combinationY of a stationary stu-d having a collar thereon and a head separated-from the collar, of a disc constituting a brush, said disc having an opening at one side in which said collar fits and which centers it on the stud, the disc also having a recess, a spiral spring in the recess, the stud and the disc each having a slit therein, the spring having ends engaging respectively in said slits, whereby the winding up of the spring before inserting one of its ends in its slit will leave the spring under compression and cause the spring to rotate the disc, and a retainer at the outer end of said recess and under said head for holding the spring in position in the recess.

AUGUST F. LUNDQUIST. 

